Add a generic section on how to mount extra data into our images

We regularly get questions about how to add binaries or other files into our images at runtime.
There are a few options that we recommend and it differs per operator because not all of them support extra_volumes, but we never wrote this down in a structured fashion and picked a recommended option.

Lets add a section to the docs and spell out the main three or four options along with pros and cons and also mention what not to do.

Possible ways:

• mount OCI artifact
• copy to PV and mount that
• init container to download and copy
• gitsync

Not recommended:

• stick binary data into a ConfigMap or Secret

定位合适的共享文档部分，并审阅现有 operator 页面如何描述运行时数据和卷选项。添加一个结构化部分，涵盖 OCI artifacts、复制到 persistent volume、init container 和 gitsync，并列出优点和缺点，同时警告不要将二进制数据放入 ConfigMaps 或 Secrets。